Flashbulbs
Flashbulbs provide light for photography where there is insufficient "available" light. Origins Before the flash bulb, artificial lighting in photography was carried out with blasting and smoking flash guns using explosive magnesium- or aluminium powder. In 1893, Chauffour made an ancestor of the flash bulb; this had magnesium ribbon in a glass bulb, and was fired electrically- but this had been designed for underwater photography. The first recognisable flash bulb was invented in 1925 by the German physician Paul Vierkötter - using flash powder in an evacuated light bulb, fired by a lamp filament. Later that year, Vierkötter made a low-pressure-filled bulb. The first actual flashbulb was the Vacu-Blitz, made in 1929 by the German company Hauff-Leonar AG on basis of a patent from Johannes Ostermeier. This patent describes the application of ultra-thin alumnium foil (0,5µ) in a glass bulb with a low pressure oxygen atmosphere. It was the first flash bulb design, which could be reproduced on a larger industrial scale. General Electric and Westinghouse acquired license rights for Ostermeier's as well as Vierkötter's patents, followed shortly thereafter by Osram from Germany. Until the late thirties the European market was dominated by the Osram Vacublitz and G.E.C.'s Sashalite bulbs. In the US, the first foil bulbs were marketed under the trade names Mazda, Westinghouse and General Electric. The wire-filled bulb was developed by Mr. van Liempt from Philips in Holland on basis of an aluminium-magnesium alloy called Hydronalium, which had an enormous strength and ductility. This allowed the high-speed production of fine flash wire (32µ) with superior uniform burning properties, which was dispersed directly into the glass bulb. The Philips Photoflux flashbulbs with Hydronalium wire were launched in the Netherlands 1934. Wabash Photolamp Corporation introduced the Hydronalium wire filled bulb on the U.S. market in 1937, under the trade name Superflash. Focal Encyclopedia of Photography, revised ed. 1969, Focal Press, London The Hauff-Leonar Vacu-Blitz Individual Bulbs Initially, flash bulbs were individual, disposable items - used once, then discarded. These are fitted into a flash gun, which may be a built-in to the camera, or an added-on accessory. Bulbs improved on earlier flash systems by safely enclosing the material which could otherwise throw burning embers over the subject and emit large quantities of smoke. Bulbs contained various materials, aluminium-, magnesium- or zirconium wire or foil. Early bulbs were very like domestic light-bulbs, including a metal cap with a screw (ES/Edison Screw) or bayonet (BC/Bayonet Cap) fitting. In the very beginning, flash guns didn't even exist and therefore the first flash bulbs had small E10 fittings, which were screwed into an ordinary pocket flash.The shutter was opened, the flash was fired and the shutter was closed again, as simple as that. When the first flash guns appeared on the market, the Edison E27 Screw became the standard, followed by cheaper bayonet fittings. Later on in the fifties, costs were further lowered by the introduction of smaller powerful bulbs with wire contacts emerging from the glass, thus eliminating the expensive fitting. Later bulb designs incorporated plastic coatings, to try to prevent bulb bursts - or at least contain the broken glass. These coatings were usually coloured blue - to give a colour temperature closer to daylight for use with colour film. One particular cause of bursting is cracking and subsequent leakage of air into the low-pressure oxygen of the bulb; to reduce the chance of this, most bulbs had a blue indicator spot on the inside, which would change colour in air. Use of this blue spot was continued in flashcubes & magicubes. Flashguns often included quite high-voltage batteries to fire the bulbs; even as late as the 1960s, bulb guns could have batteries of 20 volts or more. By the late 1960s, smaller bulbs were introduced such as the AG1 which could be fired by lower voltages, with many guns using only one or two 1.5v AA batteries. Virtually all disposable flash bulbs and systems have now been replaced by re-usable electronic flashguns. A very few photographers still use bulbs for special effects, or the sheer power that bulbs can produce; see, for example the flashbulbs.com link (below) for current usages and supplies. Synchronisation Flashes need to be synchronised to the opening of the shutter. On early systems, this was done simply by opening the shutter (or removing the lens cap) and firing the flash by hand. Electrical operation allowed automatic synchronisation to the shutter. Firing early bulbs electrically required a specialised battery of around 15-25v in the flashgun or camera, although some large bulbs were designed for 110 or 240volt mains ignition1. There are variations in synch requirements - see Flash sync for details. Flashbulb types * F''' - Fast bulbs, with time to peak approx. 5 ms and flash duration under 10 ms (at half peak), which could be used with X synch sockets of leaf shutters at speeds up to 1/100 s. im to fye folk * '''X - a German class laying between types F and M, with time to peak of 10-18 ms and most common flash duration of 8-10 ms. * M''' - Medium fast bulbs, offering time to peak 18-20 s and generally 8-12 ms flash duration. * '''S - Slow burning high power bulbs with time to peak approx. 30 ms. Due to long flash duration (some 20-30 ms) S type could be used with leaf shutters at speeds not higher than 1/20 s, but had guide number significantly higher than other flashbulb types. * FP - slow burning bulbs intended for synchronisation with focal plane shutters at any shutter speed. Type FT had time to peak of approx. 30-35 ms and 25-35 ms flash duration at half peak, with relatively even brightness. Multiple Systems These consist of a number of bulbs packaged together, with an automatic method of firing the next unused bulb. These were common on cheap, snapshot type cameras such as Instamatics and Polaroids. Individual disposable flash bulbs had several disadvantages: * Bulbs could be fiddly and slow to insert into a flashgun; the wire contacts could be bent and fail to connect, and the glass could break in the fingers. The gun itself may need to be opened and closed in addition. * Once fired, the bulb needed to be ejected; at this point it was hot enough to have blistered the glass and burn anything it landed on, and could sometimes have shattered into small sharp shards as it fired. Often a guard had to be removed from the gun before the bulb could be. * Taking another picture required the whole process to be repeated. Various systems avoided these problems by enclosing multiple bulbs into a package - with some mechanism for automatically firing the next unused bulb. This keeps the glass and contacts away from fingers and allows rapid changes. There were three major systems: Flashcubes, Magicubes and Flipflash. Flashcubes Flashcubes, introduced in the early 1960s, had four AG1-sized bulbs, on four sides of a cube, with a plastic reflector behind. The camera had a socket to insert the cube, which would rotate as the film was wound to bring the next bulb to the front. Cubes were fired electrically by lower-voltage batteries than most individual bulbs - use of two AA batteries was common. Magicubes (X- Flash Cubes) Magicubes (X-Flashcubes) were an improvement on flashcubes, introduced in 1970. They looked almost identical to the original flashcubes, but were fired mechanically by a small bar striking a pin coated in fulminating material. This simplified the system compared to flashcubes - by removing the need for a battery, and made extremely cheap flash cameras possible. Magicube sockets appeared similar to flashcube ones, but had a slightly larger slot and were distinguished by being marked with an X - similarly the cubes themselves usually had a large X on the top - and having a pin instead of electrical contacts. Flipflash Flipflash featured an array of 8 or 10 bulbs in a flat rectangular arrangement, each bulb placed horizontally, one above the other. When half the bulbs were used, the photographer had to invert the Flipflash - which had a connector on both ends - to use the remainder (hence the name). The camera had a small rectangular socket to mount the Flipflash. Flipflash was subject to several patents; to get around these, and to fit their own cameras, other manufacturers arranged theirs differently, and some had other names for the system: Philips Topflash Topflash was very similar to Flipflash, but placed the bulbs vertically, two per row in an 2×4 arrangement. Polaroid Flash Bar Another Flipflash variation. Flash Bar bulbs were placed vertically, and arranged next to each other horizontally. Both sides had bulbs, the bar being rotated to use the other side. Sylvania Flip Flash Flip Flash bulbs were arranged in a zig-zag manner. Sylvania also made a Polaroid bar arrangement. Links * Flash (including photos of Instamatic adaptors) on Mischa Koning's Kodak Classics site * Source for GE Magicubes - New old stock of GE Magicubes. * Magicube & Flashcube Photos + Tech Data on Flashbulbs.com - a current flashbulb supplier! Data on other bulbs here too. * Photos of Flipflash Assembly on protom.org * Photos of Magicube Assembly on protom.org copyright of computer * Category:flash